Biological control of cucumber green mottle mosaic virus

ABSTRACT

An attenuated strain of cucumber green mottle mosaic virus (CGMMV) is useful to protect cucumber plants from infection with the wild-type infectious CGMMV strain. The genome of the attenuated virus contains at least one mutation or group of mutations selected from c.4969G&gt;A, c.3334C&gt;T, and a group of at least six of the mutations c.315G&gt;A; c.1498A&gt;G; c.1660C&gt;T; c.3430C&gt;T; c.3528A&gt;G; c.4144C&gt;T; c.4248C&gt;T; and c.6228C&gt;T. These mutated genomes encode one or more mutations selected from R1637H in the 186 kDa readthrough replication protein, A1092V in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and at least six mutations selected from G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S in the 129 kDa replication protein and/or the 186 kDa readthrough replication protein, and the A156V mutation in the coat protein.

CROSS REFERENCE TO A RELATED APPLICATION

This application claims priority to Canadian Patent Application No. 3,017,465, filed Sep. 14, 2018, which is incorporated herein by reference in its entirety.

The Sequence Listing for this application is labeled “SeqList-31Aug19-ST25.txt”, which was created on Sep. 14, 2018, and is 290 KB. The entire content is incorporated herein by reference in its entirety.

FIELD

The present application is directed to attenuated plant viruses. More specifically, the present application provides attenuated strains of cucumber green mottle mosaic virus (CGMMV), compositions thereof, and methods of using such virus strains and compositions for biological control of plant disease.

BACKGROUND

Cucumber green mottle mosaic virus (CGMMV) is a member of the Tobamovirus genus in the family Virgaviridae. CGMMV has a 6.4-kb single-stranded, positive-sense RNA genome with a 3′ tRNA-like structure instead of a poly(A) tail. The genome contains three open reading frames (ORFs) that encode four defined proteins. The first ORF encodes a 129 kDa protein, including methyltransferase and helicase domains required for RNA replication, and a 186 kDa protein produced by readthrough translation of the ORF, including the methyltransferase and helicase domains and an additional RNA-dependent RNA polymerase (RdRp) domain. The remaining two ORFs encode a movement protein (MP) and a coat protein (CP), respectively.

CGMMV infection causes serious diseases in plants of the family Cucurbitaceae (cucurbits), including cucumber, pumpkin, watermelon, melon, squash, zucchini, gourds, gherkins and others. CGMMV was first reported in 1935 in the UK and is found in Europe, Asia, the Middle East and, since 2013, in Canada and the United States. CGMMV infection is becoming a major limiting factor with regard to production of cucurbits worldwide, and has become an increasing threat to the commercial production of cucumber and other commercially-grown cucurbit crops.

CGMMV is a seed-borne virus and can be transmitted by root-to-root contact and by transfer from contaminated seeds, soil, gardening implements such as pruners and stakes, irrigation water, packing materials, or the clothing or hands of farmers, pickers or other persons handling the plants. The CGMMV virus is extremely stable and can remain infectious under relatively extreme conditions for long periods of time. Therefore, the presence of even a few infected plants in a cucumber greenhouse can eventually lead to the spread of CGMMV infection to the entire crop.

CGMMV is responsible for a wide range of symptoms on leaves and fruits of infected plants, depending on the CGMMV strain, stage of infection and plant species. The induced symptoms include vein clearing and crumpling in young leaves, light green mottling, mosaic patterns, necrotic lesions, fruit distortion or streak, change of sugar accumulation and flavor, and premature degradation of the pulp, making the fruit unmarketable and unfit for consumption. CGMMV infection can result in substantial yield losses up to 100%, although losses of 40-80% are more common in a commercial field or greenhouse production setting, in addition to having a major impact on fruit quality, leading to low market value.

There are no known effective chemical methods for controlling virus diseases of plants, and crop protection relies completely on aspects of sanitation that may include removal of infected plants, using only virus-free seeds and vegetative stocks, using resistant varieties, and controlling transmission by contact with insects, water and humans. Two new techniques that are now being investigated for managing plant virus diseases rely on cross protection by inoculation with attenuated/mild strains and by creating transgenic or engineered resistance based on expression of the viral coat protein of a specific viral pathogen.

Cross protection is an acquired immunity phenomenon which has been demonstrated in a number of systems. The technique makes use of the observation that plants infected with an attenuated virus isolate or strain causing mild or no symptoms can develop tolerance to further infection when challenged by an isolate or strain of the same or a related virus species which causes more severe symptoms. Cross protection is virus specific, occurring only between strains of the same virus or related virus species, and is seen as an acceptable method for crop protection in greenhouse systems as it does not rely on harmful materials or chemicals. This approach was first applied successfully in several countries in the 1970s to protect tomato plants against infection with tobacco mosaic virus. More recently, in 2015, the treatment PMV™-01, which contains a mild isolate of the Chilean strain of pepino mosaic virus (PepMV), has been registered in Europe and commercially used to protect tomato plants from severe losses in quality and yield caused by aggressive infection with PepMV.

In order to develop cross protection, attenuated/mild strains of a plant virus are needed which cause no visible or only very mild symptoms but which prevent infection by strains causing more severe symptoms. Attenuated isolates advantageously have little or no impact on plant symptoms, total yield and fruit quality, and effectively protect against more virulent isolates. The following properties have been proposed as desirable criteria for an attenuated virus strain for use in crop protection:

-   -   no symptoms or very mild symptoms are induced in any of the         cultivated hosts, and the quality and quantity of the crop         products are not reduced;     -   most host tissues are fully infected systemically;     -   the attenuated strains are highly stable genetically without         mutating into a severe phenotype;     -   there is no vector transmission to other crops;     -   the attenuated strains protect against a wide range of viruses         and strains; and     -   the quality/quantity control of the inoculum and inoculations         are easy and inexpensive.

An attenuated CGMMV strain SH33b is known (Motoyoshi, F., and Nishiguchi, M. 1988. Control of virus diseases by attenuated virus strains: comparison between attenuated strains of cucumber green mottle mosaic virus and tobacco mosaic virus. Gamma Field Symposia, 27: 91-107) which induces no or only mild systematic symptoms in leaves of muskmelon plants when a low concentration of attenuated virus was used to inoculate muskmelon seedlings. However, although this strain was effective in protecting muskmelon plants from outbreaks of severe symptoms, and in eliminating wild-type CGMMV from the greenhouse, inoculation of cotyledons with higher concentrations of the purified virus led to appearance of mosaic symptoms in the upper leaves.

In addition, an attenuated CGMMV strain VIROG-43M is known (Slavokhotova, A. A., et al, American Journal of Plant Sciences (2016), 7: 724-732), which showed effectiveness in protecting inoculated cucumber plants from disease symptoms under greenhouse conditions. However, VIROG-43M itself could induce symptoms in inoculated cucumber plants after two months of inoculation. In addition, only 85% of the cucumber plants inoculated with VIROG-43M and challenged with the pathogenic CGMMV strain NC-1 were observed to be symptomless after 3 months of inoculation under laboratory greenhouse conditions.

Recently, it was reported that several attenuated CGMMV strains were obtained from a pathogenic CGMMV strain by multi site-directed mutagenesis, based on sequence comparison of related tobamoviruses (Chen, Bin, “Molecular Characterization of Viruses Infecting Greenhouse Vegetables in Ontario” (2016). Electronic Thesis and Dissertation Repository. 4222, University of Western Ontario. Available at https://ir.lib.uwo.ca/etd/4222). However, the reported mutants could develop visible mosaic symptoms in cucumber plants to various extents, although the symptoms were generally mild compared with those caused by the wild-type strain. Even the best attenuated CGMMV isolates induced symptoms in cucumber plants after 28 days post inoculation.

It is therefore desirable to provide an attenuated strain of CGMMV for protecting plants against infection with CGMMV, and in particular, for protecting plants which are susceptible to infection with CGMMV such as species of the Cucurbitaceae family.

SUMMARY

In one aspect, the present application provides an attenuated strain of cucumber green mottle mosaic virus (CGMMV) comprising a genome, wherein the genome is a polyribonucleotide having a sequence functionally equivalent to a variant of SEQ ID NO: 18, the sequence comprising at least one residue or group of residues selected from:

a) A at the position corresponding to position 4969 of SEQ ID NO:18; b) U at the position corresponding to position 3334 of SEQ ID NO: 18; and c) a group of at least six residues selected from:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO: 18;

U at the position corresponding to position 1660 of SEQ ID NO: 18;

U at the position corresponding to position 3430 of SEQ ID NO:18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

U at the position corresponding to position 4144 of SEQ ID NO:18;

U at the position corresponding to position 4248 of SEQ ID NO: 18; and

U at the position corresponding to position 6228 of SEQ ID NO: 18.

In another aspect, the present application provides a polydeoxyribonucleotide having a sequence functionally equivalent to a sequence of a cucumber green mottle mosaic virus (CGMMV) genome, wherein the sequence of the polydeoxyribonucleotide is a variant of SEQ ID NO: 18 comprising at least one residue or group of residues selected from:

a) A at the position corresponding to position 4969 of SEQ ID NO: 18; b) T at the position corresponding to position 3334 of SEQ ID NO: 18; and c) a group of at least six residues selected from:

A at the position corresponding to position 315 of SEQ ID NO:18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

T at the position corresponding to position 1660 of SEQ ID NO: 18;

T at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

T at the position corresponding to position 4144 of SEQ ID NO:18;

T at the position corresponding to position 4248 of SEQ ID NO:18; and

T at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one embodiment, the polydeoxyribonucleotide is configured for expression in a host cell. In at least one embodiment, the host cell is a microorganism. In at least one embodiment, the host cell is a plant cell.

In another aspect, the present application provides a vector comprising a polydeoxyribonucleotide as described herein. In at least one embodiment, the vector is configured to genetically modify a host cell. In at least one embodiment, the host cell is a microorganism. In at least one embodiment, the host cell is a plant cell.

A further aspect of the present application provides a genetically modified cell comprising a polydeoxyribonucleotide as described herein. In at least one embodiment, the cell is a microorganism. In at least one embodiment, the cell is a plant cell.

Yet another aspect of the present application provides a composition for preventing symptoms associated with infection by wild-type CGMMV in a plant, where the composition comprises an attenuated strain of CGMMV or a genetically modified cell as described herein and an agriculturally acceptable carrier.

In an additional aspect, the present application provides a composition for increasing resistance of a plant to infection by wild-type CGMMV, where the composition comprises an attenuated strain of CGMMV or a genetically modified cell as described herein and an agriculturally acceptable carrier.

Another aspect of the present application provides a method for preventing symptoms associated with infection by wild-type CGMMV in a plant, where the method includes inoculating the plant with an attenuated strain of CGMMV or with a genetically modified cell or with a composition as described herein.

A further aspect of the present application provides a method for increasing resistance of a plant to infection by wild-type CGMMV, where the method includes inoculating the plant with an attenuated strain of CGMMV or with a genetically modified cell or with a composition as described herein.

In a further aspect, the present application provides a genetically modified plant comprising a genome which comprises a polydeoxyribonucleotide as described herein. In at least one embodiment, the plant is a cucurbit. In at least one embodiment, the plant is a cucumber plant.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention will become apparent from the following written description and the accompanying figures, in which:

FIG. 1A is a photograph showing leaves of a cucumber plant grown for two weeks after inoculation with a clone of a wild-type cucumber green mottle mosaic virus (CGMMV) Ontario strain;

FIG. 1B is a photograph showing leaves of a cucumber plant grown for two weeks after inoculation with a wild-type CGMMV Ontario strain isolate;

FIG. 1C is a photograph showing leaves of a cucumber plant grown for two weeks in the absence of CGMMV (negative control);

FIG. 2A is a photograph showing leaves of a cucumber plant infected with wild-type CGMMV Ontario strain and grown under laboratory conditions;

FIG. 2B is a photograph showing leaves of a cucumber plant infected with the mutant CGMMV Ontario strain ONB and grown under the laboratory conditions of FIG. 2A;

FIG. 2C is photograph showing leaves of a cucumber plant infected with the mutant CGMMV Ontario strain ONM and grown under the laboratory conditions of FIG. 2A;

FIG. 2D is a photograph showing leaves of a healthy cucumber plant without CGMMV infection grown as a control under the laboratory conditions of FIG. 2A;

FIG. 3A is a photograph showing leaves of a cucumber plant infected with wild-type CGMMV Ontario strain and grown under laboratory conditions;

FIG. 3B is a photograph showing leaves of a healthy cucumber plant without CGMMV infection grown as a control under the laboratory conditions of FIG. 3A;

FIG. 3C is a photograph showing leaves of a cucumber plant exposed to an attenuated CGMMV strain according to the present invention (ONBM) and grown under the laboratory conditions of FIG. 3A;

FIG. 3D is a photograph showing leaves of a cucumber plant exposed to another attenuated CGMMV strain according to the present invention (ONBM-2) and grown under the laboratory conditions of FIG. 3A;

FIG. 3E is a photograph showing leaves of a cucumber plant exposed to yet another attenuated CGMMV strain according to the present invention (ONBM-3) and grown under the laboratory conditions of FIG. 3A;

FIG. 4A is a photograph showing leaves of a cucumber plant inoculated with an attenuated CGMMV strain according to the present invention (ONBM), then challenged with a wild-type CGMMV and grown under laboratory conditions;

FIG. 4B is a photograph showing leaves of a cucumber plant inoculated with another attenuated CGMMV strain according to the present invention (ONBM-2), then challenged with a wild-type CGMMV and grown under the laboratory conditions of FIG. 4A;

FIG. 4C is a photograph showing leaves of a cucumber plant inoculated with yet another attenuated CGMMV strain according to the present invention (ONBM-3), then challenged with a wild-type CGMMV and grown under the laboratory conditions of FIG. 4A;

FIG. 4D is a photograph showing leaves of a cucumber plant infected with wild-type CGMMV and grown under the laboratory conditions of FIG. 4A;

FIG. 4E is a photograph showing leaves of a healthy cucumber plant without CGMMV infection grown as a control under the laboratory conditions of FIG. 4A;

FIG. 5A is a photograph showing leaves of a cucumber plant grown in a commercial greenhouse and infected with a wild-type CGMMV Ontario strain;

FIG. 5B is a photograph showing a mosaic pattern on fruit of a cucumber plant grown in the commercial greenhouse of FIG. 5A and infected with a wild-type CGMMV Ontario strain;

FIG. 5C is a photograph showing curling of fruit of a cucumber plant grown in the commercial greenhouse of FIG. 5A and infected with a wild-type CGMMV Ontario strain;

FIG. 5D is a photograph showing leaves and fruit of a cucumber plant exposed to an attenuated CGMMV strain according to the present invention (ONBM-2) and grown in the commercial greenhouse of FIG. 5A;

FIG. 5E is a photograph showing leaves and fruit of a cucumber plant exposed to another attenuated CGMMV strain according to the present invention (ONBM-3) and grown in the commercial greenhouse of FIG. 5A;

FIG. 6A is a photograph showing leaves of a cucumber plant exposed to another attenuated CGMMV strain according to the present invention (ONAL-1) and grown under laboratory conditions;

FIG. 6B is a photograph showing leaves of a cucumber plant exposed to another attenuated CGMMV strain according to the present invention (ONAL-2) and grown under the laboratory conditions of FIG. 6A;

FIG. 6C is a photograph showing leaves of a cucumber plant exposed to another attenuated CGMMV strain according to the present invention (ONBM-32) and grown under the laboratory conditions of FIG. 6A;

FIG. 6D is a photograph showing leaves of a cucumber plant exposed to the mutant CGMMV Ontario strain ONB and grown under the laboratory conditions of FIG. 6A;

FIG. 6E is a photograph showing leaves of a healthy cucumber plant without CGMMV infection grown as a control under the laboratory conditions of FIG. 6A; and

FIG. 6F is a photograph showing leaves of a cucumber plant infected with wild-type CGMMV Ontario strain and grown under the laboratory conditions of FIG. 6A.

DETAILED DESCRIPTION

The present application provides an attenuated strain of the cucumber green mottle mosaic virus (CGMMV). In at least one embodiment, the attenuated CGMMV strain may be useful for protecting one or more plants against the deleterious effects of infection by a wild-type strain of CGMMV. In at least one embodiment, plants which may be protected against infection by wild-type CGMMV include but are not limited to any plant susceptible to infection by CGMMV, including but not limited to plants of the family Cucurbitaceae (cucurbits), including but not limited to varieties of cucumber (Cucumis sativus), pumpkin, watermelon, melon, squash, zucchini, gourds, gherkins and others well known in the art. In at least one embodiment, curcubits such as cucumber plants inoculated with at least one embodiment of the attenuated CGMMV strain may not show significant visible symptoms for a period of up to two months or longer after inoculation with the attenuated CGMMV strain.

In at least one embodiment, the attenuated strain of CGMMV has a genome which is a polyribonucleotide having a sequence which is functionally equivalent to a variant of SEQ ID NO: 18 including one or more variations thereof.

In at least one embodiment, the polyribonucleotide has a sequence including A at the position corresponding to position 4969 of SEQ ID NO: 18.

In at least one embodiment, the polyribonucleotide has a sequence including U at the position corresponding to position 3334 of SEQ ID NO: 18.

In at least one embodiment, the polyribonucleotide has a sequence including A at the position corresponding to position 4969 of SEQ ID NO: 18 and U at the position corresponding to position 3334 of SEQ ID NO:18.

In at least one embodiment, the polyribonucleotide has a sequence including at least six of the following residues:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

U at the position corresponding to position 1660 of SEQ ID NO: 18;

U at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

U at the position corresponding to position 4144 of SEQ ID NO:18;

U at the position corresponding to position 4248 of SEQ ID NO: 18; and

U at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one such embodiment, the polyribonucleotide sequence also includes one or both of:

U at the position corresponding to position 3334 of SEQ ID NO: 18; and

A at the position corresponding to position 4969 of SEQ ID NO: 18.

In at least one embodiment, the polyribonucleotide has a sequence including the following residues:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

U at the position corresponding to position 1660 of SEQ ID NO: 18;

U at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

U at the position corresponding to position 4144 of SEQ ID NO:18;

U at the position corresponding to position 4248 of SEQ ID NO: 18; and

U at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one such embodiment, the polyribonucleotide sequence also includes one or both of:

U at the position corresponding to position 3334 of SEQ ID NO: 18; and

A at the position corresponding to position 4969 of SEQ ID NO: 18.

As used herein, the term “polynucleotide” is intended to mean a polymeric molecule comprising two or more nucleosides linked through covalent bonds to phosphate groups, such that the 5′-hydroxyl group of a nucleoside and the 3′-hydroxyl group of an adjacent nucleoside are both covalently bonded to the same phosphate group. As understood in the art, when covalently linked together to form the polynucleotide molecule, each individual nucleoside unit is also known as a “residue”. As used herein, the term “nucleoside” is intended to mean a molecule in which a sugar moiety selected from ribose and deoxyribose is bonded to a purine or pyrimidine base moiety selected from adenine (A), guanine (G), cytosine (C), thymine (T) or uracil (U). A polynucleotide includes polynucleotides of any length, including but not limited to dinucleotides, trinucleotides, tetranucleotides, oligonucleotides and nucleic acids.

When the sugar moiety is ribose, the base is selected from A, G, C and U, and the nucleoside is referred to as a ribonucleoside. A polynucleotide comprising two or more such ribonucleosides is referred to as a polyribonucleotide or ribonucleic acid (RNA). When the sugar moiety is deoxyribose, the base is selected from A, G, C and T, and the nucleoside is referred to as a deoxyribonucleoside. A polynucleotide comprising two or more such deoxyribonucleosides is referred to as a polydeoxyribonucleotide or deoxyribonucleic acid (DNA).

In at least one embodiment, the attenuated strains can be obtained by mutation of wild type CGMMV to introduce one or more variations or mutations into the genome sequence of the wild type CGMMV. As used herein interchangeably with respect to a polynucleotide sequence, the term “variation” or “mutation” is intended to refer to a difference in the polynucleotide sequence with respect to a reference polynucleotide sequence. Variations or mutations can include substitution of one or more nucleotide residues with different nucleotide residues, insertion of additional nucleotide residues or deletion of nucleotide residues. A variation or mutation may or may not alter the open reading frame(s) of the polynucleotide or the amino acid sequence of any protein(s) encoded by the polynucleotide. In at least one embodiment, the variation or mutation is a naturally occurring variation or mutation arising without artificial intervention. In at least one embodiment, the variation or mutation is introduced intentionally by methods well known in the art, including but not limited to random mutagenesis or directed mutagenesis.

An RNA virus such as CGMMV, including but not limited to attenuated strains thereof, contains an RNA genome, in which the genetic information of the virus is stored in the form of RNA. As will be understood by a person of skill in the art, it is possible to express viral proteins encoded by such an RNA genome in a host cell which expresses genetic information from DNA by preparing a complementary DNA (cDNA) molecule carrying the same genetic information as is encoded by the RNA genome, and transforming the host cell with the cDNA such that the transformed host cell can express viral proteins encoded by the cDNA. In at least one embodiment, the virus can be assembled and/or replicated within the transformed host cell.

Therefore, another aspect of the present invention provides a polydeoxyribonucleotide having a sequence functionally equivalent to a sequence of a cucumber green mottle mosaic virus (CGMMV) genome, wherein the polydeoxyribonucleotide sequence comprises a variant of SEQ ID NO: 18 including one or more variations from SEQ ID NO: 18.

In at least one embodiment, the polydeoxyribonucleotide sequence comprises a sequence wherein the one or more variations from SEQ ID NO: 18 include A at the position corresponding to position 4969 of SEQ ID NO: 18.

In at least one embodiment, the polydeoxyribonucleotide sequence comprises a sequence wherein the one or more variations from SEQ ID NO: 18 include T at the position corresponding to position 3334 of SEQ ID NO: 18.

In at least one embodiment, the polydeoxyribonucleotide sequence comprises a sequence wherein the one or more variations from SEQ ID NO: 18 include A at the position corresponding to position 4969 of SEQ ID NO: 18 and T at the position corresponding to position 3334 of SEQ ID NO:18.

In at least one embodiment, the polydeoxyribonucleotide sequence comprises a sequence wherein the one or more variations from SEQ ID NO:18 include at least six of the following residues:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

T at the position corresponding to position 1660 of SEQ ID NO:18;

T at the position corresponding to position 3430 of SEQ ID NO:18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

T at the position corresponding to position 4144 of SEQ ID NO: 18;

T at the position corresponding to position 4248 of SEQ ID NO: 18; and

T at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one such embodiment, the one or more variations from SEQ ID NO: 18 further include one or both of:

T at the position corresponding to position 3334 of SEQ ID NO:18; and

A at the position corresponding to position 4969 of SEQ ID NO: 18.

In at least one embodiment, the polydeoxyribonucleotide sequence comprises a sequence wherein the one or more variations from SEQ ID NO: 18 include the following residues:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO: 18;

T at the position corresponding to position 1660 of SEQ ID NO:18;

T at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

T at the position corresponding to position 4144 of SEQ ID NO: 18;

T at the position corresponding to position 4248 of SEQ ID NO: 18; and

T at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one such embodiment, the one or more variations from SEQ ID NO: 18 further include one or both of:

T at the position corresponding to position 3334 of SEQ ID NO: 18; and

A at the position corresponding to position 4969 of SEQ ID NO:18.

As used herein with reference to a polynucleotide sequence, the term “functionally equivalent to” is intended to mean that the polynucleotide sequence contains the same genetic information, including but not limited to coding information, as the genetic information contained in the reference polynucleotide sequence. In at least one embodiment, a functionally equivalent polynucleotide sequence will encode the same protein or proteins as are encoded by the reference polynucleotide sequence. In at least one embodiment, a given position in the polynucleotide sequence will bear a base equivalent to the base borne by the corresponding position of the reference polynucleotide sequence. As used herein with reference to bases in functionally equivalent polynucleotide sequences, the term “equivalent” is intended to mean that the bases are either identical or provide the same coding information. Thus, the base T (which is found in polydeoxyribonucleotides) and the base U (which is found in polyribonucleotides) are considered herein to be equivalent to each other. In other words, when a polydeoxyribonucleotide sequence is functionally equivalent to a polyribonucleotide sequence, positions in the polydeoxyribonucleotide sequence which bear the base T are considered to correspond to positions in the polyribonucleotide sequence which bear the base U.

In at least one embodiment, the sequence of the polydeoxyribonucleotide is selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:53, SEQ ID NO:58, SEQ ID NO:60, and variants thereof which include at least one residue or group of residues selected from:

a) A at the position corresponding to position 4969 of SEQ ID NO: 18; b) T at the position corresponding to position 3334 of SEQ ID NO: 18; and c) a group of at least six residues selected from:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

T at the position corresponding to position 1660 of SEQ ID NO:18;

T at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

T at the position corresponding to position 4144 of SEQ ID NO:18;

T at the position corresponding to position 4248 of SEQ ID NO:18; and

T at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one embodiment, the sequence of the variant can have at least 89%, at least 90%, at least 95%, at least 99% or at least 99.9% identity to a sequence selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:53, SEQ ID NO:58 or SEQ ID NO:60, wherein the variant sequence comprises at least one residue or group of residues selected from:

a) A at the position corresponding to position 4969 of SEQ ID NO:18; b) T at the position corresponding to position 3334 of SEQ ID NO: 18; and c) a group of at least six residues selected from:

A at the position corresponding to position 315 of SEQ ID NO: 18;

G at the position corresponding to position 1498 of SEQ ID NO:18;

T at the position corresponding to position 1660 of SEQ ID NO: 18;

T at the position corresponding to position 3430 of SEQ ID NO: 18;

G at the position corresponding to position 3528 of SEQ ID NO: 18;

T at the position corresponding to position 4144 of SEQ ID NO:18;

T at the position corresponding to position 4248 of SEQ ID NO: 18; and

T at the position corresponding to position 6228 of SEQ ID NO: 18.

In at least one embodiment, the sequence of the polydeoxyribonucleotide is selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:53, SEQ ID NO:58, SEQ ID NO:60, and variants thereof which encode one or more of the proteins encoded by the polydeoxyribonucleotide having the sequence selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:53, SEQ ID NO:58 and SEQ ID NO:60.

As used herein, the term “variant” when used in reference to a polynucleotide is intended to refer to a polynucleotide which differs in its nucleotide sequence from the sequence of a reference polynucleotide to which the variant is being compared by one or more nucleotide residues. The differences between the sequence of the variant and the sequence of the reference polynucleotide, also referred to herein as variations or mutations, can include substitution of one or more nucleotide residues with different nucleotide residues, insertion of additional nucleotide residues or deletion of nucleotide residues. In certain embodiments, a variant can differ from a reference polynucleotide by substitution of one or more nucleotide residues with replacement nucleotide residues which do not alter the open reading frame(s) of the polynucleotide or the amino acid sequence of any protein(s) encoded by the polynucleotide.

As used herein, the term “variant” when used in reference to a polypeptide is intended to refer to a polypeptide which differs in its amino acid sequence from the sequence of a reference polypeptide to which the variant is being compared by one or more amino acid residues. The differences between the sequence of the variant and the sequence of the reference polypeptide can include substitution of one or more amino acid residues with different amino acid residues, insertion of additional amino acid residues or deletion of amino acid residues. In certain embodiments, a variant can differ from a reference polypeptide by conservative substitution of one or more amino acid residues with replacement amino acid residues which may have similar properties, including but not limited to charge, size and hydrophilicity, to the amino acid residues which the new residues replace. In certain embodiments, variants may completely or partially retain one or more biological functions of the reference polypeptide. In certain embodiments, variants may not retain one or more biological functions of the reference polypeptide.

As used herein, the term “percent identity” or “% identity” when used in reference to the sequence of a polypeptide or a polynucleotide is intended to mean the percentage of the total number of amino acid or nucleotide residues, respectively, in the sequence which are identical to those at the corresponding position of a reference polypeptide or polynucleotide sequence. In at least one embodiment, when the length of the variant sequence and the length of the reference sequence are not identical, percent identity can be calculated based on the total number of residues in the variant sequence or based on the total number or residues in the reference sequence. Percent identity can be measured by various local or global sequence alignment algorithms well known in the art, including but not limited to the Smith-Waterman algorithm and the Needleman-Wunsch algorithm. Tools using these or other suitable algorithms include but are not limited to BLAST (Basic Local Alignment Search Tool) and other such tools well known in the art.

In at least one embodiment, a variant polynucleotide sequence can hybridize to a polyribonucleotide or polydeoxyribonucleotide as described herein under at least moderately stringent conditions. By “at least moderately stringent hybridization conditions” it is meant that conditions are selected which promote selective hybridization between two complementary nucleic acid molecules in solution. Hybridization may occur to all or a portion of a nucleic acid sequence molecule. The hybridizing portion is typically at least 15 (e.g. 20, 25, 30, 40 or 50) nucleotides in length. Those skilled in the art will recognize that the stability of a nucleic acid duplex, or hybrid, is determined by the melting temperature (T_(m)), which in sodium-containing buffers is a function of the sodium ion concentration ([Na⁺]) and temperature (T_(m)=81.5° C. −16.6 (Log₁₀ [Na⁺])+0.41(% (G+C)−600/I), where % G+C is the percentage of cytosine and guanine nucleotides in the nucleic acid and 1 is the length of the nucleic acid in base pairs, or similar equation). Accordingly, the parameters in the wash conditions that determine hybrid stability are sodium ion concentration and temperature. In order to identify molecules that are similar, but not identical, to a known nucleic acid molecule, a 1% mismatch may be assumed to result in about a 1° C. decrease in T_(m). For example, if nucleic acid molecules are sought that have a >95% identity, the final wash temperature may be reduced by about 5° C. Based on these considerations those skilled in the art will be able to readily select appropriate hybridization conditions.

In some embodiments, stringent hybridization conditions are selected. By way of example the following conditions may be employed to achieve stringent hybridization: hybridization at 5× sodium chloride/sodium citrate (SSC)/5×Denhardt's solution/1.0% sodium dodecylsulfate (SDS) at T_(m)−5° C. based on the above equation, followed by a wash of 0.2×SSC/0.1% SDS at 60° C. Moderately stringent hybridization conditions include a washing step in 3×SSC at 42° C. It is understood, however, that equivalent stringencies may be achieved using alternative buffers, salts and temperatures. Additional guidance regarding hybridization conditions may be found in: Current Protocols in Molecular Biology, John Wiley & Sons, N.Y., 2002, and in: Sambrook et al., Molecular Cloning: a Laboratory Manual, Cold Spring Harbor Laboratory Press, 2001.

In at least one embodiment, the polyribonucleotide CGMMV genome and the functionally equivalent polydeoxyribonucleotide can each encode one or more viral proteins including but not limited to a 129 kDa protein including methyltransferase and helicase domains required for RNA replication, a 186 kDa protein including the methyltransferase and helicase domains and an additional RNA-dependent RNA polymerase (RdRp) domain, a movement protein (MP) and a coat protein (CP).

In at least one embodiment, the 129 kDa protein has an amino acid sequence comprising valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the 129 kDa protein sequence includes at least two residues selected from:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the 129 kDa protein sequence further includes valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the 129 kDa protein sequence includes at least three residues selected from:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the 129 kDa protein sequence further includes valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the 129 kDa protein sequence includes the residues:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the 129 kDa protein sequence further includes valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the sequence of the 129 kDa protein is selected from SEQ ID NO:43, SEQ ID NO:46, SEQ ID NO:49, SEQ ID NO:54, SEQ ID NO:61 and variants thereof which include valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the sequence of the 129 kDa protein is selected from SEQ ID NO:43, SEQ ID NO:46, SEQ ID NO:49, SEQ ID NO:54, SEQ ID NO:61 and variants thereof which include at least two residues selected from:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the variants of the 129 kDa protein sequence further include valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the sequence of the 129 kDa protein is selected from SEQ ID NO:43, SEQ ID NO:46, SEQ ID NO:49, SEQ ID NO:54, SEQ 1D NO:61 and variants thereof which include at least three residues selected from:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the variants of the 129 kDa protein sequence further include valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the sequence of the 129 kDa protein is selected from SEQ ID NO:43, SEQ ID NO:46, SEQ ID NO:49, SEQ ID NO:54, SEQ ID NO:61 and variants thereof which include the residues:

-   -   serine (S, Ser) at the position corresponding to position 86 of         SEQ ID NO:63;     -   glycine (G, Gly) at the position corresponding to position 480         of SEQ ID NO:63;     -   phenylalanine (F, Phe) at the position corresponding to position         534 of SEQ ID NO:63; and     -   valine (V, Val) at the position corresponding to position 1124         of SEQ ID NO:63.

In at least one such embodiment, the variants of the 129 kDa protein sequence further include valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:63.

In at least one embodiment, the 186 kDa protein has an amino acid sequence comprising histidine (H, His) at the position corresponding to position 1637 of SEQ ID NO:64.

In at least one embodiment, the 186 kDa protein sequence includes valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:64.

In at least one embodiment, the 186 kDa protein sequence includes histidine (H, His) at the position corresponding to position 1637 of SEQ ID NO:64 and valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:64.

In at least one embodiment, the 186 kDa protein sequence includes at least five residues selected from:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one such embodiment, the 186 kDa protein sequence further includes one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

In at least one embodiment, the 186 kDa protein sequence includes at least six residues selected from:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one such embodiment, the 186 kDa protein sequence further includes one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

In at least one embodiment, the 186 kDa protein sequence includes the residues:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one such embodiment, the 186 kDa protein sequence further includes one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include histidine (H, His) at the position corresponding to position 1637 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include histidine (H, His) at the position corresponding to position 1637 of SEQ ID NO:64 and valine (V, Val) at the position corresponding to position 1092 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include at least five residues selected from:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one embodiment, the variants of the 186 kDa protein sequence further include one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include at least six residues selected from:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one embodiment, the variants of the 186 kDa protein sequence further include one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

In at least one embodiment, the sequence of the 186 kDa protein is selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof which include the residues:

serine (S, Ser) at the position corresponding to position 86 of SEQ ID NO:64;

glycine (G, Gly) at the position corresponding to position 480 of SEQ ID NO:64;

phenylalanine (F, Phe) at the position corresponding to position 534 of SEQ ID NO:64;

valine (V, Val) at the position corresponding to position 1124 of SEQ ID NO:64;

aspartic acid (D, Asp) at the position corresponding to position 1157 of SEQ ID NO:64;

leucine (L, Leu) at the position corresponding to position 1362 of SEQ ID NO:64; and

serine (S, Ser) at the position corresponding to position 1397 of SEQ ID NO:64.

In at least one embodiment, the variants of the 186 kDa protein sequence further include one or both of:

-   -   valine (V, Val) at the position corresponding to position 1092         of SEQ ID NO:64; and     -   histidine (H, His) at the position corresponding to position         1637 of SEQ ID NO:64.

Because the 186 kDa protein is encoded by an open reading frame in the CGMMV genome which includes the open reading frame for the 129 kDa protein, it will be clear to the person of skill in the art that a polyribonucleotide or a polydeoxyribonucleotide as described herein which encodes a 186 kDa protein as described herein will also encode a 129 kDa protein as described herein.

In at least one embodiment, the coat protein has an amino acid sequence comprising valine (V, Val) at the position corresponding to position 156 of SEQ ID NO:65. In at least one embodiment, the sequence of the coat protein is selected from SEQ ID NO:32 and variants thereof comprising valine (V, Val) at the position corresponding to position 156 of SEQ ID NO:65.

As will be understood in the art, the degeneracy of the genetic code allows for some amino acids to be encoded by more than one codon or group of three nucleoside residues. Therefore, it is contemplated that the sequences of the present polyribonucleotide or polydeoxyribonucleotide can also include mutations other than those specifically described herein such that the polyribonucleotide or polydeoxyribonucleotide will encode proteins having amino acid sequences as described herein.

In at least one embodiment, the polydeoxyribonucleotide is configured for expression in a host cell so as to permit expression of viral proteins and/or assembly and/or replication of infectious virus in the host cell, as will be understood by those skilled in the art, who will be capable of configuring the polydeoxyribonucleotide for expression in such a host cell without undue experimentation in light of the teaching herein. In at least one embodiment, the host cell is a microorganism. In at least one embodiment, the host cell is a plant cell.

In another aspect, the present application provides a vector comprising a polydeoxyribonucleotide as described herein. In at least one embodiment, the vector is configured for use to genetically modify a cell. Thus, a further aspect of the present application provides a genetically modified cell comprising a polydeoxyribonucleotide as described herein. In at least one embodiment, the cell is a microorganism. In at least one embodiment, the cell is a plant cell. Those skilled in the art would be aware of methods for preparing such vectors and using them to genetically modify such cells.

Another aspect of the present application provides a composition for preventing symptoms associated with infection by wild-type CGMMV in a plant, where the composition comprises an attenuated strain of CGMMV or a genetically modified cell as described herein and an agriculturally acceptable carrier. In at least one embodiment, the composition comprises two or more attenuated strains of CGMMV or genetically modified cells as described herein.

As used herein, the term “carrier” is intended to refer to a diluent, adjuvant, excipient, or vehicle with which an attenuated strain of CGMMV or a genetically modified cell can be applied or administered to a plant or crop. As used herein, the term “agriculturally acceptable” is intended to refer to carriers and compositions containing such carriers that are tolerable and do not typically produce untoward reactions to a plant or crop being treated with such carriers and compositions, or to a worker applying such carriers and compositions to a plant or crop under normal agricultural conditions. Preferably, as used herein, the term “agriculturally acceptable” means approved by a regulatory agency of the federal or a state government for use in agricultural applications. Such agriculturally acceptable carriers are well known in the art.

In an additional aspect, the present application provides a composition for increasing resistance of a plant to infection by wild-type CGMMV, where the composition comprises an attenuated strain of CGMMV or a genetically modified cell as described herein and an agriculturally acceptable carrier. In at least one embodiment, the composition comprises two or more attenuated strains of CGMMV or genetically modified cells as described herein.

Another aspect of the present application provides a method for preventing symptoms associated with infection by wild-type CGMMV in a plant, where the method includes inoculating the plant with an attenuated strain of CGMMV or with a genetically modified cell as described herein. Methods of inoculating plants with viruses, including but not limited to attenuated strains thereof, and/or with cells, including but not limited to microorganisms, genetically modified to express such viruses or associated viral proteins, and/or with compositions thereof are well known in the art, and well within the capability of the skilled person in light of the teaching of the present application.

A further aspect of the present application provides a method for increasing resistance of a plant to infection by wild-type CGMMV, where the method includes inoculating the plant with an attenuated strain of CGMMV or with a genetically modified cell as described herein.

In a further aspect, the present application provides a genetically modified plant comprising a genome which comprises a polydeoxyribonucleotide as described herein. It is contemplated that such a genetically modified plant may have increased resistance to infection by wild type strains of CGMMV. In at least one embodiment, the plant is a cucurbit. In at least one embodiment, the plant is a cucumber plant.

As used herein, the terms “about” or “approximately” as applied to a numerical value or range of values are intended to mean that the recited values can vary within an acceptable degree of error for the quantity measured given the nature or precision of the measurements, such that the variation is considered in the art as equivalent to the recited values and provides the same function or result. For example, the degree of error can be indicated by the number of significant figures provided for the measurement, as is understood in the art, and includes but is not limited to a variation of ±1 in the most precise significant figure reported for the measurement. Typical exemplary degrees of error are within 20 percent (%), preferably within 10%, and more preferably within 5% of a given value or range of values. Alternatively, and particularly in biological systems, the terms “about” and “approximately” can mean values that are within an order of magnitude, preferably within 5-fold and more preferably within 2-fold of a given value. Numerical quantities given herein are approximate unless stated otherwise, meaning that the term “about” or “approximately” can be inferred when not expressly stated.

As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” in a given position including but not limited to vertical, horizontal, or adjacent to or aligned with another object, would mean that the object is either completely in that position or nearly completely in that position. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking, the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained.

The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of” an ingredient or element would either completely lack that ingredient or element, or so nearly completely lack that ingredient or element that the effect would be the same as if it completely lacked that ingredient or element. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable or significant effect thereof.

EXAMPLES

Other features of the present invention will become apparent from the following non-limiting examples which illustrate, by way of example, the principles of the invention.

Example 1: Cucumber Green Mottle Mosaic Virus (CGMMV) Ontario Strain

Isolation, Cloning and Sequencing of a Wild-Type Ontario Strain

Cucumber green mottle mosaic virus (CGMMV) Ontario strain (also referred to herein as the “wild-type” strain) was extracted from cucumber plants showing green mottle and mosaic symptoms collected from a commercial greenhouse in Ontario. cDNA was synthesized from the CGMMV RNA genome using Agilent AccuScrip™ High-Fidelity Reverse Transcriptase (Agilent) and an oligonucleotide primer having the sequence CGGCTCGAGCCCGTTTCGTCCTTTAGGGACTCGTCAGTGTACTGA-TATAAGTACAGACTGGGCCCCTACCCGGGGAAAGGGGGGATT (SEQ ID NO:1). The full-length genome of CGMMV Ontario strain was amplified from cDNA by polymerase chain reaction (PCR) using Q5™ High-fidelity 2× Master Mix (New England Biolabs) and the primers GTTTTAATTTTAAAATTAAACAAACAACAACAACAACAACAAAC (SEQ ID NO:2) and CCCCGGCTCGAGCCCGTTTCGTCCTTTAGGGACTCGT (SEQ ID NO:3). The PCR product was digested with XhoI and cloned into a binary vector pKW8 between the StuI and XhoI sites in 10-beta Escherichia coli (New England Biolabs) by electroporation. The whole cDNA genome was sequenced using primers which were designed based on analysis of genome sequences published in GenBank for other CGMMV strains. The sequences of the primers are listed in Table 1 below.

TABLE 1 Primers used to sequence the cDNA genome of CGMMV wild-type Ontario strain Primer sequence (5′ to 3′) Sequence identifier CGTACCTCCTGAATGCATCTATC SEQ ID NO: 4 CGGTAACTATACGCAGCACTT SEQ ID NO: 5 CAGTTTAGGGTCGATGGTGATG SEQ ID NO: 6 CAAGGCCTTAGTGTGGAAGAA SEQ ID NO: 7 CTCGCTTCCGGTGATGATTT SEQ ID NO: 8 GTCGGAACCTCGATGACTTTAC SEQ ID NO: 9 GTGACGATACCACTCGCATAAT SEQ ID NO: 10 CTGATGGTCCATACGGGATTAC SEQ ID NO: 11 GGCCTTAACTAGGCACACTAAG SEQ ID NO: 12 CCGGGTCTTCTTGAGAATCTTG SEQ ID NO: 13 TGGCTTGGATGTGGTCTATG SEQ ID NO: 14 GGTCGATAAGTTGCTCCCTAAC SEQ ID NO: 15 TAGTCGAGTCTGTCGTCTCTTC SEQ ID NO: 16 CCTGTGTTGAGGCCTATCTTC SEQ ID NO: 17

The full-length cDNA genome sequence of CGMMV Ontario strain is shown below.

(SEQ ID NO: 18) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTGGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGAAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTCTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGCGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTAATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCCTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAACCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGCTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The 129 kDa protein encoded by the wild type CGMMV Ontario strain has the following sequence.

(SEQ ID NO: 63) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVIISVKAIKVSGAGILRPELTKIKGKIITFT QSDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVL VALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTK.

The 186 kDa protein encoded by the wild type CGMMV Ontario strain has the following sequence.

(SEQ ID NO: 64) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTKXQLMQN SLYVHRNIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHPKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKPEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The coat protein encoded by the wild type CGMMV Ontario strain has the following sequence.

(SEQ ID NO: 65) MAYNPITPSKLIAFSASYVPVRTLLNFLVASQGTAFQTQAGRDSFRESLS ALPSSVVDINSRFPNAGFYAFLNGPVLRPIFVSLLSSTDTRNRVIEVVDP SNPTTAESLNAVKRTDDASTAARAEIDNLIESISKGFDVYDRASFEAAFS VVWSEATTSKA.

Infection of Cucumber Plants with the Wild-Type Ontario Strain

The CGMMV Ontario strain clone was transformed into Agrobacterium tumefaciens strain EHA105 by electroporation. The Agrobacterium transformants were selected on LB medium plates containing 50 μg/ml of kanamycin and 20 μg/ml of rifampicin. After confirmation by colony PCR, the Agrobacterium transformants carrying CGMMV Ontario strain were cultured overnight at 30° C. with shaking at 200 rpm in LB medium (lysogeny broth, also known as Luria-Bertani medium) containing 50 μg/ml of kanamycin and 20 μg/ml of rifampicin. The overnight culture was used to inoculate fresh LB medium containing 50 μg/ml of kanamycin, 20 μg/ml of rifampicin, 10 mM MES (2-(N-morpholino)ethanesulfonic acid), and 200 μM acetosyringone (3′,5′-dimethoxy-4′-hydroxyacetophenone) and the culture was incubated with shaking at 30° C. until the optical density at 600 nm (OD₆₀₀) reached between 0.5 and 1.0.

Bacterial cells were harvested by centrifugation at 4000 g for 10 minutes and resuspended in the same volume of Agrobacterium induction buffer (10 mM MES, 200 μM acetosyringone). The suspended cells were incubated at room temperature with gentle shaking (50 rpm) for 3-4 hours. The Agrobacterium cells were inoculated into the cotyledon of 1-2 week-old cucumber plants by leaf infiltration using a 1 ml needleless syringe. After incubation for a further two weeks under laboratory greenhouse conditions (16 h daylight at 22° C., 8 h darkness at 20° C.), cucumber plant leaves were sampled and tested for the presence of CGMMV by ELISA using a commercial ELISA kit for detecting CGMMV (Agdia) and following the manufacturer's directions. The results shown in Table 2 demonstrated that the clone of CGMMV Ontario strain was fully infectious.

TABLE 2 ELISA results of cucumber plants inoculated with the CGMMV clone and wild-type CGMMV isolate after 2 weeks inoculation. Optical Density at 405 nm Treatment Plant 1 Plant 2 Plant 3 Plant 4 Plant 5 CGMMV Clone 1.419 1.401 1.348 1.463 1.378 Wild-type CGMMV 1.609 1.734 1.169 1.457 1.357 isolate Negative −0.01 0.003 −0.002 0.002 −0.001

In addition, as seen in FIGS. 1A to C, the CGMMV Ontario strain clone expressed in Agrobacterium tumefaciens produced similar symptoms in infected leaves (FIG. 1A) as those produced by infection with the wild-type CGMMV Ontario strain isolate (FIG. 1B). FIG. 1C shows uninfected leaves as a negative control.

Example 2: Attenuated CGMMV Strains

Mutant CGMMV Ontario Strain ONB

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out to introduce mutations (c.1498A>G; c.3430C>T; c.3528A>G; c.4248C>T; and c.6228C>T) corresponding to those observed in the attenuated SH33b strain of CGMMV (Tan et al, Ann. Phytopathol. Soc. Jpn (1997), 63(6): 470-474). These mutations resulted in amino acid substitutions in the encoded viral proteins (E480G and A1124V in the 129 kDa protein; E480G, A1124V, N1157D, and P1397S in the 186 kDa protein; and A156V in the coat protein).

Mutations were introduced using the QuikChange™ Lightning Multi Site-Directed Mutagenesis kit (Agilent Technologies), following the manufacturer's instructions, and using the mutagenic primers listed in Table 3. Nucleotide residues indicated in bold indicate sites of mutation. The resulting mutant CGMMV strain was designated Ontario strain ONB.

TABLE 3 Primers used to produce mutant CGMMV Ontario strain ONB Sequence Primer sequence (5′ to 3′) Identifier TCTTAAATCCGCCGTAGGAGGACTAGGTGATTGCG SEQ ID NO: 19 CGCAATCACCTAGTCCTCCTACGGCGGATTTAAGA SEQ ID NO: 20 TCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAA SEQ ID NO: 21 GGTCG CGACCTTTTCCACATCCACTATTATACTTGTAACTG SEQ ID NO: 22 CATCGA CTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTT SEQ ID NO: 23 AG CTAACAGGGAGGAAAATATCACGATGGACATACA SEQ ID NO: 24 GTGAG TCTAAGTTTTTCTTTTACACTAGGAAAAAATCAGAA SEQ ID NO: 25 GATCTGCAGGA TCCTGCAGATCTTCTGATTTTTTCCTAGTGTAAAAGA SEQ ID NO: 26 AAAACTTAGA GTAGTCTGGTCAGAGGTTACCACCTCGAAAGCT SEQ ID NO: 27 AGCTTTCGAGGTGGTAACCTCTGACCAGACTAC SEQ ID NO: 28

The cDNA genome sequence of CGMMV strain ONB is shown below.

(SEQ ID NO: 29) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTGGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGGAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTCTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCCTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAATCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGTTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The 129 kDa protein encoded by CGMMV strain ONB has the following sequence.

(SEQ ID NO: 30) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTK.

The 186 kDa protein encoded by CGMMV strain ONB has the following sequence.

(SEQ ID NO: 31) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTKXQLMQN SLYVHRDIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHPKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKSEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The coat protein encoded by CGMMV strain ONB has the following sequence.

(SEQ ID NO: 32) MAYNPITPSKLIAFSASYVPVRTLLNFLVASQGTAFQTQAGRDSFRESLS ALPSSVVDINSRFPNAGFYAFLNGPVLRPIFVSLLSSTDTRNRVIEVVDP SNPTTAESLNAVKRTDDASTAARAEIDNLIESISKGFDVYDRASFEAAFS VVWSEVTTSKA.

Mutant CGMMV Ontario Strain ONM

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above, but using the mutagenic primers listed in Table 4, to introduce mutations (c.315G>A; c.1660C>T; and c.4144C>T) corresponding to those observed in the attenuated VIROG-43M strain (Slavokhotova, A. A., et al, American Journal of Plant Sciences (2016), 7: 724-732). Nucleotide residues indicated in bold indicate sites of mutation. These mutations resulted in amino acid substitutions in the encoded viral proteins (G86S and S534F in the 129 kDa protein; and G86S, S534F and P1362L in the 186 kDa protein). The resulting mutant CGMMV strain was designated Ontario strain ONM.

TABLE 4 Primers used to produce mutant CGMMV Ontario strain ONM Sequence Primer Sequence (5′ to 3′) Identifier CTCCCTTGCGGGTAGTCTGAGGCTCCT SEQ ID NO: 33 AGGAGCCTCAGACTACCCGCAAGGGAG SEQ ID NO: 34 AAAGATCGAGAGAGAGAGTGTCTTTGAGTTGCTCGC SEQ ID NO: 35 GCGAGCAACTCAAAGACACTCTCTCTCTCGATCTTT SEQ ID NO: 36 CTTGCAAACTATTGTTTATCACCTTAAAGTGGTAAA SEQ ID TGCAGTTTTCG NO: 37 CGAAAACTGCATTTACCACTTTAAGGTGATAAACAA SEQ ID TAGTTTGCAAG NO: 38

The cDNA genome sequence of CGMMV strain ONM is shown below.

(SEQ ID NO: 39) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTAGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGAAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTTTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGCGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTAATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCTTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAACCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGCTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The 129 kDa protein encoded by CGMMV strain ONM has the following sequence.

(SEQ ID NO: 40) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTK.

The 186 kDa protein encoded by CGMMV strain ONM has the following sequence.

(SEQ ID NO: 41) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTKXQLMQN SLYVHRNIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHLKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKPEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The mutant clones ONB and ONM were each transformed into Agrobacterium tumefaclens strain EHA105 by electroporation and used to inoculate the cotyledon of 1-2 week old cucumber plants under laboratory greenhouse conditions using the method described in Example 1. As seen in FIG. 2B, two weeks after inoculation, mutant strain ONB induced visible symptoms including mottle and mosaic symptoms, Likewise, as seen in FIG. 2C, two weeks after inoculation, mutant strain ONM also induced visible symptoms, although these symptoms were milder than those induced by the mutant ONB strain. For comparison, FIG. 2A shows a plant exhibiting symptoms induced by inoculation with the wild-type Ontario strain CGMMV under the same conditions, and FIG. 2D shows an uninfected control plant grown under the same conditions.

Mutant CGMMV Ontario Strain ONBM

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above to introduce mutations corresponding to those of mutants ONB and ONM (c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T). These mutations resulted in amino acid substitutions in the encoded viral proteins (G86S, E480G, S534F and A1124V in the 129 kDa protein; G86S, E480G, S534F, A1124V, N1157D, P1362L, and P1397S in the 186 kDa protein; and A156V in the coat protein). The resulting mutant CGMMV strain was designated Ontario strain ONBM.

The cDNA genome sequence of CGMMV strain ONBM is shown below.

(SEQ ID NO: 42) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTAGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGGAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTTTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCTTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAATCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGTTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONBM differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO:18) at least in that:

the nucleotide at position 315 of SEQ ID NO:42 is A;

the nucleotide at position 1498 of SEQ ID NO:42 is G;

the nucleotide at position 1660 of SEQ ID NO:42 is T;

the nucleotide at position 3430 of SEQ ID NO:42 is T;

the nucleotide at position 3528 of SEQ ID NO:42 is G;

the nucleotide at position 4144 of SEQ ID NO:42 is T;

the nucleotide at position 4248 of SEQ ID NO:42 is T; and

the nucleotide at position 6228 of SEQ ID NO:42 is T.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM has the following sequence.

(SEQ ID NO: 43) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTK.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM differs from the 129 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:63) at least in that:

position 86 of SEQ ID NO:43 is serine (S, Ser);

position 480 of SEQ ID NO:43 is glycine (G, Gly);

position 534 of SEQ ID NO:43 is phenylalanine (F, Phe); and

position 1124 of SEQ ID NO:43 is valine (V, Val).

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM has the following sequence.

(SEQ ID NO: 44) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTKXQLMQN SLYVHRDIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHLKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKSEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that:

position 86 of SEQ ID NO:44 is serine (S, Ser);

position 480 of SEQ ID NO:44 is glycine (G, Gly);

position 534 of SEQ ID NO:44 is phenylalanine (F, Phe);

position 1124 of SEQ ID NO:44 is valine (V, Val);

position 1157 of SEQ ID NO:44 is aspartic acid (D, Asp);

position 1362 of SEQ ID NO:44 is leucine (L, Leu); and

position 1397 of SEQ ID NO:44 is serine (S, Ser).

The coat protein encoded by the attenuated CGMMV strain ONBM has the sequence of SEQ ID NO:32 and differs from the coat protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:65) at least in that position 156 of SEQ ID NO:32 is valine (V, Val).

Mutant CGMMV Ontario Strain ONBM-2

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above to introduce mutations corresponding to those of mutants ONB and ONM (c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T) in addition to the mutation c.3334C>T introduced by randomly replacing C by T during PCR amplification. These mutations resulted in amino acid substitutions in the encoded viral proteins (G86S, E480G, S534F, A1092V and A1124V in the 129 kDa protein; G86S, E480G, S534F, A1092V, A1124V, N1157D, P1362L, and P1397S in the 186 kDa protein; and A156V in the coat protein). The resulting mutant CGMMV strain was designated Ontario strain ONBM-2.

The cDNA genome sequence of CGMMV strain ONBM-2 is shown below.

(SEQ ID NO: 45) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTAGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGGAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTTTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGTCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCTTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAATCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGTTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONBM-2 differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO: 18) at least in that:

the nucleotide at position 315 of SEQ ID NO:45 is A;

the nucleotide at position 1498 of SEQ ID NO:45 is G;

the nucleotide at position 1660 of SEQ ID NO:45 is T;

the nucleotide at position 3334 of SEQ ID NO:45 is T;

the nucleotide at position 3430 of SEQ ID NO:45 is T;

the nucleotide at position 3528 of SEQ ID NO:45 is G;

the nucleotide at position 4144 of SEQ ID NO:45 is T;

the nucleotide at position 4248 of SEQ ID NO:45 is T; and

the nucleotide at position 6228 of SEQ ID NO:45 is T.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-2 has the following sequence.

(SEQ ID NO: 46) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVIIFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEF MVKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFS VWFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNK ALVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVR KVQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTS SDELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDE IRNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGT LSPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWA DVKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPL DEEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASL GSTLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVL ASDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKE AIVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRA CALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALK ISGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPR DVTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFT QSDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVL VALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTK.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-2 differs from the 129 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:63) at least in that:

position 86 of SEQ ID NO:46 is serine (S, Ser);

position 480 of SEQ ID NO:46 is glycine (G, Gly);

position 534 of SEQ ID NO:46 is phenylalanine (F, Phe);

position 1092 of SEQ ID NO:46 is valine (V, Val); and

position 1124 of SEQ ID NO:46 is valine (V, Val).

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-2 has the following sequence.

(SEQ ID NO: 47) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTKXQLMQN SLYVHRDIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHLKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKSEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-2 differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that:

position 86 of SEQ ID NO:47 is serine (S, Ser);

position 480 of SEQ ID NO:47 is glycine (G, Gly);

position 534 of SEQ ID NO:47 is phenylalanine (F, Phe);

position 1092 of SEQ ID NO:47 is valine (V, Val);

position 1124 of SEQ ID NO:47 is valine (V, Val);

position 1157 of SEQ ID NO:47 is aspartic acid (D, Asp);

position 1362 of SEQ ID NO:47 is leucine (L, Leu); and

position 1397 of SEQ ID NO:47 is serine (S, Ser).

The coat protein encoded by the attenuated CGMMV ONBM-2 strain has the sequence of SEQ ID NO:32 and differs from the coat protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:65) at least in that position 156 of SEQ ID NO:32 is valine (V, Val).

Mutant CGMMV Ontario Strain ONBM-3

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above to introduce mutations corresponding to those induced in the cDNA genome of the cloned CGMMV Ontario strain mutants ONB and ONM (c.315G>A; c.1498A>G; c.1660C>T; c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; and c.6228C>T) in addition to the mutation c.4969G>A introduced by randomly replacing G by A during PCR amplification. These mutations resulted in amino acid substitutions in the encoded viral proteins (G86S, E480G, S534F and A1124V in the 129 kDa protein; G86S, E480G, S534F, A1124V, N1157D, P1362L, P1397S and R1637H in the 186 kDa protein; and A156V in the coat protein). The resulting mutant CGMMV strain was designated Ontario strain ONBM-3.

The cDNA genome sequence of CGMMV strain ONBM-3 is shown below.

(SEQ ID NO: 48) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTAGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGGAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTTTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCTTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAATCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCACCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGTTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONBM-3 differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO:18) at least in that:

the nucleotide at position 315 of SEQ ID NO:48 is A;

the nucleotide at position 1498 of SEQ ID NO:48 is G;

the nucleotide at position 1660 of SEQ ID NO:48 is T;

the nucleotide at position 3430 of SEQ ID NO:48 is T;

the nucleotide at position 3528 of SEQ ID NO:48 is G;

the nucleotide at position 4144 of SEQ ID NO:48 is T;

the nucleotide at position 4248 of SEQ ID NO:48 is T;

the nucleotide at position 4969 of SEQ ID NO:48 is A; and

the nucleotide at position 6228 of SEQ ID NO:48 is T.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-3 has the following sequence.

(SEQ ID NO: 49) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTK.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-3 differs from the 129 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:63) at least in that:

position 86 of SEQ ID NO:49 is serine (S, Ser);

position 480 of SEQ ID NO:49 is glycine (G, Gly);

position 534 of SEQ ID NO:49 is phenylalanine (F, Phe); and

position 1124 of SEQ ID NO:49 is valine (V, Val).

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-3 has the following sequence.

(SEQ ID NO: 50) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTKXQLMQN SLYVHRDIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHLKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKSEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKHLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-3 differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that:

position 86 of SEQ ID NO:50 is serine (5, Ser);

position 480 of SEQ ID NO:50 is glycine (G, Gly);

position 534 of SEQ ID NO:50 is phenylalanine (F, Phe);

position 1124 of SEQ ID NO:50 is valine (V, Val);

position 1157 of SEQ ID NO:50 is aspartic acid (D, Asp);

position 1362 of SEQ ID NO:50 is leucine (L, Leu);

position 1397 of SEQ ID NO:50 is serine (S, Ser); and

position 1637 of SEQ ID NO:50 is histidine (H, His).

The coat protein encoded by the attenuated CGMMV strain ONBM-3 has the sequence of SEQ ID NO:32 and differs from the coat protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:65) at least in that position 156 of SEQ ID NO:32 is valine (V, Val).

Mutant CGMMV Ontario Strain ONAL-1

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above, using the mutagenic primers listed in Table 5 to introduce the mutation c.3334C>T. Nucleotide residues indicated in bold indicate sites of mutation. This mutation resulted in an A1092V amino acid substitution in the encoded viral 129 kDa and 186 kDa proteins. The resulting mutant CGMMV strain was designated Ontario strain ONAL-1.

TABLE 5 Primers used to produce mutant CGMMV Ontario strain ONAL-1 Sequence Primer Sequence (5′ to 3′) Identifier TGTGGTGAATCACGGACAATTAAACCTATCGGAGTCG SEQ ID NO: 51 CGACTCCGATAGGTTTAATTGTCCGTGATTCACCACA SEQ ID NO: 52

The cDNA genome sequence of CGMMV strain ONAL-1 is shown below.

(SEQ ID NO: 53) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTGGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGAAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTCTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGTCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGCGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTAATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCCTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAACCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCGCCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGCTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONAL-1 differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO: 18) at least in that the nucleotide at position 3334 of SEQ ID NO:53 is T.

The 129 kDa protein encoded by the attenuated CGMMV strain ONAL-1 has the following sequence.

(SEQ ID NO: 54) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTK.

The 129 kDa protein encoded by the attenuated CGMMV strain ONAL-1 differs from the 129 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:63) at least in that position 1092 of SEQ ID NO:54 is valine (V, Val).

The 186 kDa protein encoded by the attenuated CGMMV strain ONAL-1 has the following sequence.

(SEQ ID NO: 55) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTKXQLMQN SLYVHRNIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHPKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKPEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKRLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONAL-1 differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that position 1092 of SEQ ID NO:55 is valine (V, Val).

Mutant CGMMV Ontario Strain ONAL-2

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above, using the mutagenic primers listed in Table 6 to introduce the mutation c.4969G>A. Nucleotide residues indicated in bold indicate sites of mutation. This mutation resulted in an R1637H amino acid substitution in the encoded viral 186 kDa protein. The resulting mutant CGMMV strain was designated Ontario strain ONAL-2.

TABLE 6 Primers used to produce mutant CGMMV Ontario strain ONAL-2 Sequence Primer Sequence (5′ to 3′) Identifier CTATATAAAGACTACGGAAAAGGTGCTTATCACTCAAAT SEQ ID ACTTGCAC NO: 56 GTGCAAGTATTTGAGTGATAAGCACCTTTTCCGTAGTCT SEQ ID TTATATAG NO: 57

The cDNA genome sequence of CGMMV strain ONAL-2 is shown below.

(SEQ ID NO: 58) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTGGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGAAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTCTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGCCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGCGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTAATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCCTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAACCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCACCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGCTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONAL-2 differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO:18) at least in that the nucleotide at position 4969 of SEQ ID NO:58 is A.

The 186 kDa protein encoded by the attenuated CGMMV strain ONAL-2 has the following sequence.

(SEQ ID NO: 59) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGGLRLLELEYMMMQVP YGSPCYDIGGNYTQIILFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHV QRHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNH AVSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIG AQFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEF MVKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFS VWFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNK ALVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVR KVQIELMSDKVVIEARGLLRRFADSLKSAVEGLGDCVYDALVQTGWFDTS SDELKVLLPEPFMTFSDYLEGMYEADAKIERESVSELLASGDDLFKKIDE IRNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGT LSPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWA DVKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPL DEEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASL GSTLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVL ASDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKE AIVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRA CALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALK ISGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPR DVTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFT QSDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIARDSPHVL VALTRHTKAMVYYTVVFDAVTSIIADVEKVDQSILTMFATTVPTKXQLMQ NSLYVHRNIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDN EFNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLV AMIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASS IQSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQ SEYPALQTIVYHPKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKPED LQEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILA WMWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASML PLDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYF CGKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSL FNGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKHLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONAL-2 differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that position 1637 of SEQ ID NO:59 is histidine (H, His).

Mutant CGMMV Ontario Strain ONBM-32

Directed mutation of the cDNA genome of the cloned CGMMV Ontario strain (Example 1) was carried out as described above to introduce mutations corresponding to those induced in the cDNA genome of the cloned CGMMV Ontario strain mutants ONBM, ONAL-1 and ONAL-2 (c.315G>A; c.1498A>G; c.1660C>T; c.3334C>T c.3430C>T; c.3528A>G; c.4144C>T; c.4248C>T; c.4969G>A; and c.6228C>T). These mutations resulted in amino acid substitutions in the encoded viral proteins (G86S, E480G, S534F, A1092V and A1124V in the 129 kDa protein; G86S, E480G, S534F, A1092V, A1124V, N1157D, P1362L, P1397S and R1637H in the 186 kDa protein; and A156V in the coat protein). The resulting mutant CGMMV strain was designated Ontario strain ONBM-32.

The cDNA genome sequence of CGMMV strain ONBM-32 is shown below.

(SEQ ID NO: 60) GTTTTAATTTTTAAAATTAAACAAACAACAACAACAACAACAAACAATTT AAAACAACAATGGCAAACATTAATGAACAAATCAACAACCAACGCGACGC CGCGGCCAGCGGGAGAAACAATCTCGTTAGCCAATTGGCGTCAAAAAGGG TGTATGACGAGGCTGTTCGCTCGTTGGATCATCAAGACAGACGCCCAAAA ATGAACTTTTCTCGTGTGGTCAGCACAGAGCACACCAGGCTTGTAACTGA TGCGTATCCGGAGTTTTCGATTAGCTTTACCGCCACCAAGAACTCTGTAC ACTCCCTTGCGGGTAGTCTGAGGCTCCTTGAACTGGAATATATGATGATG CAAGTGCCCTACGGCTCACCTTGTTATGATATCGGCGGTAACTATACGCA GCACTTGTTCAAAGGTAGATCATATGTGCATTGCTGCAATCCGTGCCTGG ATCTTAAAGATGTTGCGAGGAACGTGATGTATAACGATATGGTCACACAA CATGTACAGAGGCACAAGGGATCTGGCGGGTGCAGACCTCTTCCAACTTT TCAGATAGATGCATTCAGGAGGTACGATAATTCTCCCTGTGCGGTCACCT GTTCAGACGTTTTCCAAGAGTGTTCCTATGATTTTGGGAGCGGTAGGGAT AATCATGCAGTCTCGCTGCATTCAATCTACGATATCCCTTATTCTTCGAT CGGACCTGCTCTTCATAGGAAGAACGTGCGAGTTTGTTATGCAGCCTTTC ACTTCTCGGAGGCATTGCTTTTAGGTTCACCTGTAGGTAATTTAAATAGT ATTGGGGCTCAGTTTAGGGTCGATGGTGATGATGTGCATTTTCTTTTTAG TGAAGAGTCTACTTTGCATTATACTCATAGTTTAGAAAATATCAAATTAA TTGTGATGCGTACTTATTTTCCTGCTGATGATAGGTACGTGTATATTAAG GAGTTTATGGTCAAGCGTGTGGATACTTTCTTCTTTAGGTTGGTCAGAGC AGACACACATATGCTTCATAAATCTGTGGGGCACTATTCAAAATCGAAAT CTGAGTACTTTGCGCTGAATACCCCTCCGATCTTCCAAGACAAAGCCACG TTTTCTGTGTGGTTTCCTGAGGCGAAGCGTAAGGTGTTGATACCCAAGTT TGAACTTTCAAGATTCCTTTCTGGGAATGTGAAAATCTCTAGGATGCTTG TCGATGCTGATTTCGTCCATACCATTATTAATCACATTAGCACGTATGAT AATAAGGCCTTAGTGTGGAAGAATGTTCAGTCCTTTGTGGAATCTATACG CTCAAGAGTAATTGTAAACGGAGTTTCGGTGAAATCTGAATGGAACGTAC CGGTTGATCAGCTCACTGATATCTCGTTCTCGATATTCCTTCTCGTGAAG GTTAGGAAGGTACAGATCGAGTTAATGTCTGATAAAGTTGTAATCGAGGC GAGGGGCTTGCTCCGGAGGTTCGCAGACAGTCTTAAATCCGCCGTAGGAG GACTAGGTGATTGCGTCTATGATGCTCTAGTTCAAACCGGCTGGTTTGAT ACCTCTAGCGACGAACTGAAAGTTTTGCTACCTGAACCGTTTATGACCTT TTCGGATTATCTTGAAGGGATGTACGAGGCAGATGCAAAGATCGAGAGAG AGAGTGTCTTTGAGTTGCTCGCTTCCGGTGACGATTTGTTCAAGAAAATC GATGAGATAAGAAACAATTACAGTGGAGTCGAATTTGATGTAGAGAAATT CCAGGAATTTTGCAAGGAACTGAATGTTAATCCTATGCTAATTGGCCATG TTATCGAAGCTATTTTTTCGCAGAAAGCTGGGGTGACAGTAACGGGTCTG GGTACCCTCTCTCCTGAGATGGGTGCTTCTGTTGCGTTATCCAATACCTC TGTAGATACATGTGAAGATATGGATGTAACTGAAGATATGGAGGATATAG TGTTGATGGCGGACAAGAGTCATTCTTACATGTCCCCAGAAATGGCGAGA TGGGCTGATGTAAAATACGACAACAATAAAGGGGGCCTGGTCGAATACAA AGTCGGAACCTCGATGACTTTACCTGCCACCTGGGCAGAGAAGGGTAAGG CTGTCTTACCGTTGTCGGGGATCTGTGTGAGGAAACCCCAATTTTCGAAG CCGCTTGATGAGGAAGACGACTTGAGGTTATCAAACATGAATTTCTTTAA GGTGAGCGATCTGAAGTTGAAGAAAACTATCACTCCAGTTGTTTACACTG GGACCATTCGAGAGAGGCAAATGAAGAATTATATTGATTACTTATCGGCC TCTCTTGGTTCTACGCTGGGTAATCTGGAGAGAATTGTGCGGAGTGATTG GAACGGTACCGAGGAGAGTATGCAAACGTTCGGGTTGTATGACTGCGAAA AGTGCAAGTGGTTACTGTTACCAGCCGAAAAGAAGCACGCATGGGCTGTG GTTCTGGCAAGTGATGATACCACTCGCATAATCTTCCTCTCATATGACGA ATCTGGTTCTCCCATAATTGATAAGAGAAACTGGAAGCGATTTGCTGTTT GCTCTGAGACCAAAGTCTATAGCGTAATTCGTAGTTTAGAGGTACTAAAT AAGGAAGCAATAGTCGACCCCGGGGTTCATATAACATTAGTTGACGGAGT GCCGGGTTGTGGAAAGACCGCCGAAATTATAGCGAGGGTCAATTGGAAAA CCGATCTAGTATTGACTCCCGGGAGGGAGGCGGCTGCTATGATTAGGCGG AGGGCCTGCGCCCTGCACAAGTCACCTGTGGCAACCAGTGACAACGTTAG AACTTTCGATTCTTTTGTGATGAATAAGAAAATCTTCAAGTTTGACGCTG TCTATGTTGACGAGGGTCTGATGGTCCATACGGGTTTACTTAATTTTGCG TTGAAGATCTCAGGTTGTAAAAAGGCCTTCGTCTTTGGTGATGCTAAGCA AATCCCGTTTATAAACAGAGTCATGAATTTTGATTATCCTAAGGAGTTAA GAACTTTAATAGTCGATAATGTAGAGCGTAGGTATGTTACCCATAGGTGT CCTAGAGATGTCACTAGTTTTCTTAATACTATTTACAAAGCCGCTGTCGC TACTACTAGTCCGGTTGTACATTCTGTGAAGGCGATTAAAGTGTCAGGGG CCGGTATTCTGAGGCCCGAGTTGACGAAGATCAAAGGAAAGATAATAACG TTTACTCAATCTGATAAGCAGTCCTTGATCAAGAGTGGGTACAATGACGT GAACACTGTGCATGAAATTCAGGGAGAAACCTTTGAAGAGACGGCGGTTG TGCGTGCCACCCCGACTCCGATAGGTTTAATTGTCCGTGATTCACCACAT GTACTAGTGGCCTTAACGAGGCACACTAAGGCAATGGTGTATTATACTGT TGTGTTCGATGCAGTTACAAGTATAATAGTGGATGTGGAAAAGGTCGACC AGTCGATCTTGACTATGTTTGCTACCACTGTGCCTACCAAATAGCAATTA ATGCAGAACTCACTGTATGTCCATCGTGATATTTTCCTCCCTGTTAGTAA AACGGGGTTTTATACAGACATGCAGGAGTTCTATGATAGATGCCTTCCTG GGAATTCCTTCGTGCTGAATGATTTCGATGCCGTAACCATGCGGTTGAGG GACAACGAATTTAACCTACAACCTTGTAGGCTAACCTTAAGTAATTTAGA TCCAGTACCCGCTTTGGTTAAGAGTGAAGCGCAGAATTTTCTGATTCCCG TTTTGCGTACGGCCTGTGAAAGGCCGCGCATTCCAGGTCTCCTTGAAAAT CTTGTAGCTATGATAAAGAGGAATATGAATACTCCTGATCTAGCTGGGAC TGTGGATATAACTAATATGTCGATTTCTATAGTAGATAACTTCTTTTCTT CTTTTGTTAGAGACGAGGTTTTGCTTGATCATTTAGATTGTGTTAGGGCT AGTTCCATTCAAAGTTTTTCTGATTGGTTTTCGTGTCAGCCAACCTCGGC GGTTGGTCAATTAGCTAATTTCAATTTCATAGATTTGCCTGCCTTTGATA CTTATATGCACATGATTAAGCGGCAGCCCAAGAGTCGGTTGGATACTTCG ATTCAGTCTGAATATCCGGCCTTGCAAACTATTGTTTATCACCTTAAAGT GGTAAATGCAGTTTTCGGTCCGGTTTTTAAGTATTTGACCACCAAGTTTC TTAGCATGGTAGATAGTTCTAAGTTTTTCTTTTACACTAGGAAAAAATCA GAAGATCTGCAGGAATTTTTCTCAGATCTCTCTTCCCATTCTGATTATGA GATTCTTGAGCTGGATGTTTCTAAATATGACAAGTCACAATCCGATTTCC ATTTCTCTATTGAGATGGCAATTTGGGAAAAATTGGGGCTGGACGATATT TTGGCTTGGATGTGGTCTATGGGTCACAAGAGAACTATACTGCAAGATTT CCAAGCCGGGATAAAGACGCTCATTTACTATCAACGGAAGTCTGGTGATG TAACTACTTTCATAGGTAATACCTTTATTATCGCAGCGTGTGTAGCTAGT ATGTTGCCGTTAGACAAGTGTTTTAAAGCTAGTTTTTGTGGTGATGATTC GCTGATCTACCTTCCTAAGGGTTTGGAGTATCCTGATATACAGGCTACTG CCAACTTGGTTTGGAATTTTGAGGCGAAACTTTTCCGAAAGAAGTATGGT TACTTCTGTGGGAAGTATATAATTCACCATGCCAACGGCTGTATTGTTTA CCCTGACCCTTTAAAATTAATTAGTAAATTAGGTAATAAGAGTCTTGTAG GGTATGAGCATGTTGAGGAGTTTCGTATATCTCTCCTCGACGTCGCTCAT AGTTTGTTTAATGGTGCTTATTTCCATTTACTCGACGATGCAATCCACGA ATTATTTCCTAACGCTGGGGGTTGCAGTTTTGTAATTAATTGTTTGTGCA AGTATTTGAGTGATAAGCACCTTTTCCGTAGTCTTTATATAGATGTCTCT AAGTAAGGTGTCGGTCGAGAACTCATTGAAACCCGAGAAGTTTGTTAAAA TCTCTTGGGTCGATAAGTTGCTCCCTAACTATTTTTCCATTCTTAAGTAT TTATCTATAACTGACTTTAGCGTAGTTAAAGCTCAGAGCTATGAATCCCT CGTGCCTGTCAAGTTGTTGCGTGGTGTTGATCTTACAAAACACCTTTATG TCACATTGTTGGGCGTTGTGGTTTCTGGTGTATGGAACGTACCGGAATCC TGTAGGGGTGGTGCTACTGTTGCTCTGGTTGACACAAGGATGCATTCTGT TGCAGAGGGAACTATATGCAAATTTTCAGCTCCCGCCACCGTCCGCGAAT TCTCTGTTAGGTTCATACCTAACTATTCTGTCGTGGCTGCGGATGCCCTT CGCGATCCTTGGTCTTTATTTGTGAGACTCTCTAATGTAGGGATTAAAGA TGGTTTCCATCCTTTGACCTTAGAGGTCGCTTGTTTAGTCGCTACAACTA ACTCTATTATCAAAAAGGGTCTTAGAGCTTCTGTAGTCGAGTCTGTCGTC TCTTCCGATCAGTCCATTGTCCTAGATTCTTTATCCGAGAAAGTTGAACC TTTCTTTGATAAAGTTCCTATTTCGGCGGCTGTGATGGCAAGAGACCCCA GTTATAGGTCTAGGTCGCAGTCTGTCGGTGGTCGTGGTAAGCGGCATTCT AAACCTCCAAATCGGAGGTTGGACTCTGCTTCTGAAGAGTCCAGTTCTGT TTCTTTCGAAGATGGCTTACAATCCGATCACACCTAGCAAACTTATTGCG TTTAGTGCTTCTTATGTTCCCGTCAGGACTTTACTTAATTTTCTAGTTGC TTCACAAGGTACCGCCTTCCAGACTCAAGCGGGAAGAGATTCTTTCCGCG AGTCCCTGTCTGCGTTACCCTCGTCTGTCGTAGATATTAATTCTAGGTTC CCAAATGCGGGTTTTTACGCTTTCCTCAACGGTCCTGTGTTGAGGCCTAT CTTCGTTTCGCTTCTTAGCTCTACGGATACGCGTAATAGGGTCATTGAGG TTGTAGATCCTAGCAATCCTACGACTGCTGAGTCGCTTAACGCTGTAAAG CGTACTGATGACGCATCTACGGCCGCTAGGGCTGAAATAGATAATTTAAT AGAGTCTATTTCTAAGGGTTTTGATGTTTATGATAGGGCTTCATTTGAAG CCGCGTTTTCGGTAGTCTGGTCAGAGGTTACCACCTCGAAAGCTTAGCTT CGAGGGTCTTCTGATGGTGGTGCACACCAAAGTGCATAGTGCTTTCCCGT TCACTTAAATCGAACGGTTTGCTCATTGGTTTGCGGAAACCTCTCACGTG TGGCGTTGAAGTTTCTATGGGCAGTAATTCTGCAAGGGGTTCGAATCCCC CCTTTCCCCGGGTAGGGGCCCA.

The cDNA genome sequence of the attenuated CGMMV strain ONBM-32 differs from the cDNA genome sequence of the wild type CGMMV Ontario strain (SEQ ID NO:18) at least in that:

the nucleotide at position 315 of SEQ ID NO:60 is A;

the nucleotide at position 1498 of SEQ ID NO:60 is G;

the nucleotide at position 1660 of SEQ ID NO:60 is T;

the nucleotide at position 3334 of SEQ ID NO:60 is T;

the nucleotide at position 3430 of SEQ ID NO:60 is T;

the nucleotide at position 3528 of SEQ ID NO:60 is G;

the nucleotide at position 4144 of SEQ ID NO:60 is T;

the nucleotide at position 4248 of SEQ ID NO:60 is T;

the nucleotide at position 4969 of SEQ ID NO:60 is A; and

the nucleotide at position 6228 of SEQ ID NO:60 is T.

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-32 has the following sequence.

(SEQ ID NO: 61) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTK

The 129 kDa protein encoded by the attenuated CGMMV strain ONBM-32 differs from the 129 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:63) at least in that:

position 86 of SEQ ID NO:61 is serine (S, Ser);

position 480 of SEQ ID NO:61 is glycine (G, Gly);

position 534 of SEQ ID NO:61 is phenylalanine (F, Phe);

position 1092 of SEQ ID NO:61 is valine (V, Val); and

position 1124 of SEQ ID NO:61 is valine (V, Val).

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-32 has the following sequence.

(SEQ ID NO: 62) MANINEQINNQRDAAASGRNNLVSQLASKRVYDEAVRSLDHQDRRPKMNF SRVVSTEHTRLVTDAYPEFSISFTATKNSVHSLAGSLRLLELEYMMMQVP YGSPCYDIGGNYTQHLFKGRSYVHCCNPCLDLKDVARNVMYNDMVTQHVQ RHKGSGGCRPLPTFQIDAFRRYDNSPCAVTCSDVFQECSYDFGSGRDNHA VSLHSIYDIPYSSIGPALHRKNVRVCYAAFHFSEALLLGSPVGNLNSIGA QFRVDGDDVHFLFSEESTLHYTHSLENIKLIVMRTYFPADDRYVYIKEFM VKRVDTFFFRLVRADTHMLHKSVGHYSKSKSEYFALNTPPIFQDKATFSV WFPEAKRKVLIPKFELSRFLSGNVKISRMLVDADFVHTIINHISTYDNKA LVWKNVQSFVESIRSRVIVNGVSVKSEWNVPVDQLTDISFSIFLLVKVRK VQIELMSDKVVIEARGLLRRFADSLKSAVGGLGDCVYDALVQTGWFDTSS DELKVLLPEPFMTFSDYLEGMYEADAKIERESVFELLASGDDLFKKIDEI RNNYSGVEFDVEKFQEFCKELNVNPMLIGHVIEAIFSQKAGVTVTGLGTL SPEMGASVALSNTSVDTCEDMDVTEDMEDIVLMADKSHSYMSPEMARWAD VKYDNNKGGLVEYKVGTSMTLPATWAEKGKAVLPLSGICVRKPQFSKPLD EEDDLRLSNMNFFKVSDLKLKKTITPVVYTGTIRERQMKNYIDYLSASLG STLGNLERIVRSDWNGTEESMQTFGLYDCEKCKWLLLPAEKKHAWAVVLA SDDTTRIIFLSYDESGSPIIDKRNWKRFAVCSETKVYSVIRSLEVLNKEA IVDPGVHITLVDGVPGCGKTAEIIARVNWKTDLVLTPGREAAAMIRRRAC ALHKSPVATSDNVRTFDSFVMNKKIFKFDAVYVDEGLMVHTGLLNFALKI SGCKKAFVFGDAKQIPFINRVMNFDYPKELRTLIVDNVERRYVTHRCPRD VTSFLNTIYKAAVATTSPVVHSVKAIKVSGAGILRPELTKIKGKIITFTQ SDKQSLIKSGYNDVNTVHEIQGETFEETAVVRATPTPIGLIVRDSPHVLV ALTRHTKAMVYYTVVFDAVTSIIVDVEKVDQSILTMFATTVPTKXQLMQN SLYVHRDIFLPVSKTGFYTDMQEFYDRCLPGNSFVLNDFDAVTMRLRDNE FNLQPCRLTLSNLDPVPALVKSEAQNFLIPVLRTACERPRIPGLLENLVA MIKRNMNTPDLAGTVDITNMSISIVDNFFSSFVRDEVLLDHLDCVRASSI QSFSDWFSCQPTSAVGQLANFNFIDLPAFDTYMHMIKRQPKSRLDTSIQS EYPALQTIVYHLKVVNAVFGPVFKYLTTKFLSMVDSSKFFFYTRKKSEDL QEFFSDLSSHSDYEILELDVSKYDKSQSDFHFSIEMAIWEKLGLDDILAW MWSMGHKRTILQDFQAGIKTLIYYQRKSGDVTTFIGNTFIIAACVASMLP LDKCFKASFCGDDSLIYLPKGLEYPDIQATANLVWNFEAKLFRKKYGYFC GKYIIHHANGCIVYPDPLKLISKLGNKSLVGYEHVEEFRISLLDVAHSLF NGAYFHLLDDAIHELFPNAGGCSFVINCLCKYLSDKHLFRSLYIDVSK.

The 186 kDa protein encoded by the attenuated CGMMV strain ONBM-32 differs from the 186 kDa protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:64) at least in that:

position 86 of SEQ ID NO:62 is serine (S, Ser);

position 480 of SEQ ID NO:62 is glycine (G, Gly);

position 534 of SEQ ID NO:62 is phenylalanine (F, Phe);

position 1092 of SEQ ID NO:62 is valine (V, Val);

position 1124 of SEQ ID NO:62 is valine (V, Val);

position 1157 of SEQ ID NO:62 is aspartic acid (D, Asp);

position 1362 of SEQ ID NO:62 is leucine (L, Leu);

position 1397 of SEQ ID NO:62 is serine (S, Ser); and

position 1637 of SEQ ID NO:62 is histidine (H, His).

The coat protein encoded by the attenuated CGMMV strain ONBM-32 has the sequence of SEQ ID NO:32 and differs from the coat protein encoded by the wild type CGMMV Ontario strain (SEQ ID NO:65) at least in that position 156 of SEQ ID NO:32 is valine (V, Val).

Example 3: Inoculation of Cucumber Plants with the Attenuated CGMMV ONBM, ONBM-2 and ONBM-3 Strains

The attenuated CGMMV Ontario strains ONBM, ONBM-2 and ONBM-3 were transformed into Agrobacterium tumefaciens strain EHA105 by electroporation and used to inoculate the cotyledon of 1-2 week old cucumber plants as described in Example 1. Two weeks after inoculation, plants were inspected for visible symptoms of CGMMV infection and leaf tissue was collected for detection of virus infection. The attenuated CGMMV Ontario strains ONBM, ONBM-2 and ONBM-3 were detected in leaf tissue by real-time TaqMan reverse-transcription PCR (Chen et al., Journal of Virological Methods (2008), 149: 326-329). As seen from the results shown in FIGS. 3A to 3E, no symptoms were induced by inoculation with ONBM (FIG. 3C), ONBM-2 (FIG. 3D) or ONBM-3 (FIG. 3E) while the typical green mottle and mosaic symptoms were induced by inoculation with wild-type CGMMV under laboratory greenhouse conditions (FIG. 3A). FIG. 3B shows leaves of a healthy cucumber plant grown as a control.

The attenuated CGMMV Ontario strains ONBM, ONBM-2 and ONBM-3 were tested for the protection of cucumber plants from infection by wild-type CGMMV. Seven day old cucumber seedlings were inoculated with CGMMV Ontario strains ONBM, ONBM-2 or ONBM-3 or were not inoculated, under laboratory greenhouse conditions as described in Example 1. Two weeks after inoculation, the plants were challenged with wild-type CGMMV Ontario strain. As seen from the results shown in FIG. 4A to 4E, no symptoms were observed 4 weeks after challenge with the wild-type CGMMV on plants inoculated with ONBM-2 (FIG. 4B) or ONBM-3 (FIG. 4C), and very mild or undetectable symptoms were observed 4 weeks after challenge with the wild-type CGMMV on plants inoculated with ONBM (FIG. 4A). In contrast, the typical green mottle and mosaic symptoms were observed in uninoculated plants challenged with wild-type CGMMV (FIG. 4D). FIG. 4E shows leaves of an uninoculated and unchallenged healthy cucumber plant (control).

The attenuated CGMMV Ontario strains ONBM-2 and ONBM-3 were tested for the protection of cucumber plants from natural infection by wild-type CGMMV under commercial greenhouse conditions. Cotyledons of 1-2 week old cucumber plants were inoculated with the strains ONBM-2 and ONBM-3 as described in Example 1. Uninoculated cucumber plants were used as a control. As seen from the results presented in FIGS. 5A to 5E, no visible symptoms were observed on the cucumber plants after inoculation with ONBM-2 or ONBM-3 for a period of 100 days (until the end of production) in a commercial greenhouse. In contrast, uninoculated plants showed symptoms of CGMMV infection of leaves, showing green mottle and mosaic symptoms (FIG. 5A), and CGMMV infection of fruits (FIG. 5B and FIG. 5C). The cucumber fruits produced from the cucumber plants inoculated with the attenuated strains ONBM-2 (FIG. 5D) or ONBM-3 (FIG. 5E) were healthy, while the uninoculated cucumber plants produced diseased and unmarketable cucumber fruits showing mosaic and soft (FIG. 5B) or curling (FIG. 5C) symptoms. In addition, over a harvest period of two months, the cucumber fruit yield was increased by 12.7% during the second month of harvest for plants treated with the attenuated CGMMV ONBM-3 strain compared with untreated cucumber plants exposed to natural CGMMV infection in commercial greenhouse conditions.

Example 4: Inoculation of Cucumber Plants with the Attenuated CGMMV ONAL-1, ONAL-2 and ONBM-32 Strains

The attenuated CGMMV Ontario strains ONAL-1, ONAL-2, and ONBM-32 were transformed into Agrobacterium tumefaciens strain EHA105 by electroporation. Agrobacterium tumefaciens containing mutant CGMMV strains ONAL-1, ONAL-2, ONBM-32 and ONB (Example 2) were used to inoculate the cotyledon of 1-2 week old cucumber plants using the method described in Example 1. Two weeks after inoculation, plants were inspected for visible symptoms of CGMMV infection and leaf tissue was collected for detection of virus infection. The attenuated CGMMV Ontario strains ONAL-1, ONAL-2, ONBM-32 and ONB were detected in leaf tissue by real-time TaqMan reverse-transcription PCR (Chen et al., Journal of Virological Methods (2008), 149: 326-329).

As seen from the results shown in FIGS. 6A to 6F, plants inoculated with either mutant strains ONAL-1 (FIG. 6A) or ONAL-2 (FIG. 6B) under laboratory greenhouse conditions showed mild symptoms compared with plants inoculated with the wild-type CGMMV Ontario strain, which showed typical green mottle and mosaic symptoms (FIG. 6F). No symptoms were observed after inoculation with the mutant strain ONBM-32 (FIG. 6C). The symptoms observed after inoculation with mutant strain ONAL-2 (FIG. 6B) were milder than those observed after inoculation with mutant strain ONAL-1 (FIG. 6A), and milder than those observed after inoculation with mutant strain ONB (FIG. 6D). FIG. 1E shows leaves of a healthy cucumber plant grown as a control.

The embodiments described herein are intended to be illustrative of the present compositions and methods and are not intended to limit the scope of the present invention. Various modifications and changes consistent with the description as a whole and which are readily apparent to the person of skill in the art are intended to be included. The appended claims should not be limited by the specific embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. 

1. An attenuated strain of cucumber green mottle mosaic virus (CGMMV) comprising a genome, wherein the genome is a polyribonucleotide having a sequence functionally equivalent to a variant of SEQ ID NO:18, the sequence comprising at least one residue or group of residues selected from: a) A at a position corresponding to position 4969 of SEQ ID NO:18; b) U at a position corresponding to position 3334 of SEQ ID NO: 18; and c) a group of at least six residues selected from: A at a position corresponding to position 315 of SEQ ID NO: 18; G at a position corresponding to position 1498 of SEQ ID NO:18; U at a position corresponding to position 1660 of SEQ ID NO: 18; U at a position corresponding to position 3430 of SEQ ID NO: 18; G at a position corresponding to position 3528 of SEQ ID NO:18; U at a position corresponding to position 4144 of SEQ ID NO:18; U at a position corresponding to position 4248 of SEQ ID NO:18; and U at a position corresponding to position 6228 of SEQ ID NO:18.
 2. The attenuated strain according to claim 1 wherein the sequence of the polyribonucleotide comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO: 18 and U at the position corresponding to position 3334 of SEQ ID NO:
 18. 3. The attenuated strain according to claim 1 wherein the sequence of the polyribonucleotide comprises: A at the position corresponding to position 315 of SEQ ID NO: 18; G at the position corresponding to position 1498 of SEQ ID NO: 18; U at the position corresponding to position 1660 of SEQ ID NO:18; U at the position corresponding to position 3430 of SEQ ID NO: 18; G at the position corresponding to position 3528 of SEQ ID NO: 18; U at the position corresponding to position 4144 of SEQ ID NO:18; U at the position corresponding to position 4248 of SEQ ID NO: 18; and U at the position corresponding to position 6228 of SEQ ID NO:
 18. 4. The attenuated strain according to claim 3 wherein the sequence of the polyribonucleotide further comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO:18 and U at the position corresponding to position 3334 of SEQ ID NO:18.
 5. A polydeoxyribonucleotide having a sequence functionally equivalent to the sequence of the polyribonucleotide according to claim 1, wherein the sequence of the polydeoxyribonucleotide is a variant of SEQ ID NO: 18 comprising at least one residue or group of residues selected from: a) A at the position corresponding to position 4969 of SEQ ID NO: 18; b) T at the position corresponding to position 3334 of SEQ ID NO:18; and c) a group of at least six residues selected from; A at the position corresponding to position 315 of SEQ ID NO:18; G at the position corresponding to position 1498 of SEQ ID NO:18; T at the position corresponding to position 1660 of SEQ ID NO:18; T at the position corresponding to position 3430 of SEQ ID NO:18; G at the position corresponding to position 3528 of SEQ ID NO:18; T at the position corresponding to position 4144 of SEQ ID NO:18; T at the position corresponding to position 4248 of SEQ ID NO:18; and T at the position corresponding to position 6228 of SEQ ID NO:
 18. 6. The polydeoxyribonucleotide according to claim 5 wherein the sequence of the polydeoxyribonucleotide comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO:18 and T at the position corresponding to position 3334 of SEQ ID NO:18.
 7. The polydeoxyribonucleotide according to claim 5 wherein the sequence of the polydeoxyribonucleotide comprises: A at the position corresponding to position 315 of SEQ ID NO:18; G at the position corresponding to position 1498 of SEQ ID NO: 18; T at the position corresponding to position 1660 of SEQ ID NO:18; T at the position corresponding to position 3430 of SEQ ID NO:18; G at the position corresponding to position 3528 of SEQ ID NO:18; T at the position corresponding to position 4144 of SEQ ID NO:18; T at the position corresponding to position 4248 of SEQ ID NO: 18; and T at the position corresponding to position 6228 of SEQ ID NO:18.
 8. The polydeoxyribonucleotide according to claim 7 wherein the sequence of the polydeoxyribonucleotide comprises one or more of A at the position corresponding to position 4969 of SEQ ID NO:18 and T at the position corresponding to position 3334 of SEQ ID NO:
 18. 9. The polydeoxyribonucleotide according to claim 5 wherein the sequence of the polydeoxyribonucleotide is selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:53, SEQ ID NO:58, SEQ ID NO:60, and variants thereof.
 10. The polydeoxyribonucleotide according to claim 5 wherein the sequence of the polydeoxyribonucleotide is selected from SEQ ID NO:42, SEQ ID NO:45, SEQ ID NO:48, SEQ ID NO:60, and variants thereof.
 11. The polydeoxyribonucleotide according to claim 5, wherein the polydeoxyribonucleotide encodes one or more proteins selected from: a 129 kDa protein having an amino acid sequence selected from SEQ ID NO:43, SEQ ID NO:46, SEQ ID NO:49, SEQ ID NO:54, SEQ ID NO:61 and variants thereof; a 186 kDa protein having an amino acid sequence selected from SEQ ID NO:44, SEQ ID NO:47, SEQ ID NO:50, SEQ ID NO:55, SEQ ID NO:59, SEQ ID NO:62 and variants thereof; and a coat protein having an amino acid sequence selected from SEQ ID NO:32 and variants thereof.
 12. A vector comprising the polydeoxyribonucleotide according to claim
 5. 13. A genetically modified cell, wherein the cell expresses the polydeoxyribonucleotide according to claim
 5. 14. The genetically modified cell according to claim 13 wherein the cell is a microorganism.
 15. The genetically modified cell according to claim 13 wherein the cell is a plant cell.
 16. A composition for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the composition comprises an attenuated strain of CGMMV according to claim 1 and an agriculturally acceptable carrier.
 17. A composition for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the composition comprises a genetically modified cell according to claim 13 and an agriculturally acceptable carrier.
 18. A method for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the method comprises inoculating the plant with an attenuated strain of CGMMV according to claim
 1. 19. A method for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the method comprises inoculating the plant with a genetically modified cell according to claim
 13. 20. A method for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the method comprises inoculating the plant with a composition according to claim
 16. 21. A method for preventing symptoms associated with infection by wild-type CGMMV in a plant or for increasing resistance of a plant to infection by wild-type CGMMV, wherein the method comprises inoculating the plant with a composition according to claim
 17. 22. An attenuated strain of cucumber green mottle mosaic virus (CGMMV) comprising a genome, wherein the genome is a polyribonucleotide encoding a 186 kDa protein having an amino acid sequence comprising at least one residue or group of residues selected from: histidine at the position corresponding to position 1637 of SEQ ID NO:64; valine at the position corresponding to position 1092 of SEQ ID NO:64; and a group of at least five residues selected from: serine at the position corresponding to position 86 of SEQ ID NO:64; glycine at the position corresponding to position 480 of SEQ ID NO:64; phenylalanine at the position corresponding to position 534 of SEQ ID NO:64; valine at the position corresponding to position 1124 of SEQ ID NO:64; aspartic acid at the position corresponding to position 1157 of SEQ ID NO:64; leucine at the position corresponding to position 1362 of SEQ ID NO:64; and serine at the position corresponding to position 1397 of SEQ ID NO:64.
 23. The attenuated strain according to claim 22, wherein the polyribonucleotide further encodes a coat protein having an amino acid sequence comprising valine at the position corresponding to position 156 of SEQ ID NO:65.
 24. The attenuated strain according to claim 22, wherein the amino acid sequence of the 186 kDa protein comprises at least one residue selected from histidine at the position corresponding to position 1637 of SEQ ID NO:64 and valine at the position corresponding to position 1092 of SEQ ID NO:64.
 25. The attenuated strain according to claim 22, wherein the amino acid sequence of the 186 kDa comprises at least five residues selected from: serine at the position corresponding to position 86 of SEQ ID NO:64; glycine at the position corresponding to position 480 of SEQ ID NO:64; phenylalanine at the position corresponding to position 534 of SEQ ID NO:64; valine at the position corresponding to position 1124 of SEQ ID NO:64; aspartic acid at the position corresponding to position 1157 of SEQ ID NO:64; leucine at the position corresponding to position 1362 of SEQ ID NO:64; and serine at the position corresponding to position 1397 of SEQ ID NO:64.
 26. The attenuated strain according to claim 25, wherein the amino acid sequence of the 186 kDa protein further comprises at least one residue selected from histidine at the position corresponding to position 1637 of SEQ ID NO:64 and valine at the position corresponding to position 1092 of SEQ ID NO:64. 